Thread Starter


Joined Mar 30, 2021
  • I am in the process of using a pic18f46k22 to design a time domain reflectometer in Proteus, using MicroC . I'm testing it bit by bit. The PIC generates a pulse, pulse goes through a transistor to create a fast falling edge, edge goes to transmission line, the reflection is fed to a comparator which produces a pulse whose length is equal to the distance between the start of the transmission line and the reflection. I have to find the length of this pulse. The heart of the low-cost TDR system is a peripheral called the Charge Time Measurement Unit (CTMU). A CTMU peripheral on a microcontroller (MCU) can be used to measure time with a high degree of precision and resolution For this I want to use the CTMU. The rising edge of the pulse is EDGE1 and the falling edge is EDGE2. I'm using the TDR as Soil moisture sensor ? I'm searching about CTMU setting



Joined Jun 5, 2013
Does the CTMU have more resolution than the timer with input capture? If not, the latter is the normal way of measuring a pulse width.